In certain cases crypto code needs to zeroize their local blake2b_ctx or blake2s_ctx structures after use to avoid leaking sensitive material. Provide blake2b_zeroize_ctx() and blake2s_zeroize_ctx() helper functions that e.g. can be used with __cleanup() to automatically zeroize the structures when they go out of scope. While we're at it, replace the related memzero_explicit() calls in lib/crypto/blake2*.c with calls to the new helper functions. Signed-off-by: Thomas Huth <thuth@redhat.com> Link: https://patch.msgid.link/20260916095022.604354-8-thuth@redhat.com Signed-off-by: Eric Biggers <ebiggers@kernel.org>